package homework.mid_autumn_festival.string_exercise;

public class ToUpperCaseDemo {
    public static void main(String[] args) {
        String str = "我爱Java";
        String upper = str.toUpperCase();
        System.out.println(upper);//我爱JAVA

        String lower = str.toLowerCase();
        System.out.println(lower);//我爱java
    }
}
